I personally fast twenty hours at separate intervals during the week. What this does is it allows the small intestine to empty fully while I am sleeping and become dormant. That allows me to not break my fast for the next half day.
I can actually go well beyond this but energy will then be noticeably depleted. Yet because the small intestine remains dormant, hunger itself is not obvious. Some energy can be provided with honeyed teas which never get past the stomach.
Yes, we all need to engineer fasts into our life routines. Mine certainly works well enough and stresses nothing. It may even be the best approach unless there is additional benefit from a protracted fast that justifies the real effort.